D50 - is my shutter dying?
It looks like at shutter speeds below about 100, it is working fine. Above 100, I see a fuzzy dark line along the bottom of the pictures, taking up maybe the 1/16th of the frame.
The D50 uses an electronic shutter (CCD based) for speeds higher than 1/90, the physical shutter still operates at this same speed even when the camera uses (say) 1/1000. I'd suspect that the mirror mechanism is worn, try shooting with the camera upside-down and see if it makes a difference.